An interrupt may be an asynchronous signal indicating a need for attention or a synchronous event in software indicating a need for a change in execution. Thus, to ensure an optimum performance of an operating system, the processing of interrupts requires knowledge of an interrupt latency that is time based. The interrupt latency for operating systems may be measured to determine a time between a generation of the interrupt by a device and a servicing of the device that generated the interrupt. Often, devices are serviced as soon as the device's interrupt handler is executed. A callback subroutine for the interrupt handler of the operating system or a device driver may be triggered by the reception of the interrupt. However, the functionality of the interrupt handler is varied as a function of the reason for the interrupt and the speed at which the interrupt handler completes its task.
Conventional means for measuring the interrupt latency requires expensive and/or cumbersome external hardware. For example, an oscilloscope may be included to enable an observation of constantly varying signal voltages to determine the interrupt latency. In another example, a logic analyzer may be included to display signals of a digital circuit which are too fast to be observed and presents the signals for observation for a device under test. Additional hardware such as those described above are required in conventional measuring systems to measure interrupt latency for non-periodic interrupt sources or other interrupt sources that have an interrupt signal assertion time that cannot be predicted.